Cold box for cryogenic distilling plant

Abstract

The distillation unit includes at least one cryogenic distilling column and at least one heat exchanger, arranged in a chamber with a double casing in which the intermediate partition contains a solid insulator. The unit can be on board offshore floating terminals and drilling platforms.

What is claimed is:  
     
       1. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall, and a solid insulator supporting the inner wall of the enclosure and interposed between the floors of the two walls, said space being substantially free of any solid insulator; and  
       legs which pass with a leaktight seal through the floor of the inner wall and bear on the floor of the outer wall and support the distillation column and the heat exchanger.  
     
     
       2. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall,  
       said space being substantially free of any solid insulator and  
       the inner wall equipped with a valve for limiting its internal pressure.  
     
     
       3. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall,  
       said space being substantially free of any solid insulator and  
       means for introducing a dry gas inside the inner wall and inside the wall cavity of the enclosure.  
     
     
       4. The unit according to  claim 3 , wherein said dry gas comprises an inert gas. 
     
     
       5. The unit according to  claim 3 , further comprising a valve for limiting the internal pressure of the wall cavity. 
     
     
       6. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall,  
       said space being substantially free of any solid insulator and  
       means for introducing a dry gas inside the inner wall or inside the wall cavity of the enclosure.  
     
     
       7. The unit according to  claim 6 , wherein said dry gas comprises an inert gas. 
     
     
       8. The unit according to  claim 6 , further comprising a valve for limiting the internal pressure of the wall cavity. 
     
     
       9. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall,  
       said space being substantially free of any solid insulator and  
       wherein the enclosure is fixed to an offshore structure.  
     
     
       10. The unit according to  claim 9 , wherein the enclosure is fixed to a support which is itself fixed to a base of said structure by means of piles. 
     
     
       11. The unit according to  claim 9 , wherein said structure comprises an oil platform or a barge. 
     
     
       12. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall,  
       there being neither an insulator in loose bulk form nor an adsorbent within said space and  
       wherein the heat exchanger is provided with additional insulation.  
     
     
       13. The unit according to  claim 12 , wherein said heat exchanger is lagged with an insulator in sheet or strip form. 
     
     
       14. A cryogenic distillation unit, comprising: 
       a distillation equipment including at least one cryogenic distillation column and at least one heat exchanger; and  
       means for thermally insulating this equipment;  
       said insulating means comprising a double-walled enclosure, said enclosure comprising an inner wall and an outer wall and, between said walls, a wall cavity which contains a solid insulator, the distillation equipment being arranged in a space defined by said inner wall,  
       there being neither an insulator in loose bulk form nor an adsorbent within said space and  
       wherein internals of the enclosure, whose operating temperature is different from that of the distillation column, are provided with additional insulation.  
     
     
       15. The unit according to  claim 14 , wherein said internals are lagged with an insulator in sheet or strip form.